Make fallback implementation of pg_memory_barrier() work in 9.2 and 9.3.

tglsfdc · tglsfdc · commit 992df96580c5 · 2016-04-16T10:42:07.000-04:00
Back-patch 9.4-era commit 44cd47c into 9.2 and 9.3. As with my back-patches of yesterday, this was not seen as necessary at the time because we didn't expect barrier.h to need to work before 9.4, but commit 37de8de invalidated that theory. Per an attempt to run gaur and pademelon over old branches they've not been run on since ~2013.
diff --git a/src/backend/main/main.c b/src/backend/main/main.c
@@ -42,6 +42,8 @@
 
 #include "bootstrap/bootstrap.h"
 #include "postmaster/postmaster.h"
+#include "storage/barrier.h"
+#include "storage/spin.h"
 #include "tcop/tcopprot.h"
 #include "utils/help_config.h"
 #include "utils/memutils.h"
@@ -311,6 +313,12 @@ startup_hacks(const char *progname)
 
 	}
 #endif   /* WIN32 */
+
+	/*
+	 * Initialize dummy_spinlock, in case we are on a platform where we have
+	 * to use the fallback implementation of pg_memory_barrier().
+	 */
+	SpinLockInit(&dummy_spinlock);
 }
 
 
